Parts of Milling Machine and Their Types,Operation

Hey everyone, today we’re going to talk about milling machines. We’ll cover everything related to them, including the different parts, types, and how to operate these machines. So, stick around as we delve into the world of milling machines!

The milling machine stands out as one of the most frequently employed machines, second only to the lathe machine in common usage. It belongs to the category of manufacturing machines, alongside counterparts such as the drilling machine, shaper machine, and planer machine.

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Primarily, the milling machine finds its application in crafting flat surfaces, slots, splines, keyways, sprockets, and gears. It’s worth noting that while slotting machines, which I’ve previously covered, can also create slots and keyways, the milling machine remains a versatile tool in this manufacturing realm.

What is Milling?

Milling is a machining process that involves the removal of material from a workpiece using rotary cutters. The milling machine, equipped with various cutting tools, is used to shape and finish a wide range of materials such as metal, wood, plastics, and composites. In the milling process, the workpiece is secured to a worktable or fixture, and the milling cutter rotates at a high speed, cutting into the material to produce the desired shape or features.

There are different types of milling operations, each serving specific purposes. Some common milling operations include face milling, where the cutting tool removes material from the face of the workpiece, and peripheral milling, where the cutter removes material from the periphery of the workpiece. Other operations include slot milling, keyway milling, and contour milling, each tailored to create specific shapes, slots, or features on the workpiece.

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Overall, milling is a versatile and widely used machining technique in manufacturing and metalworking processes, allowing for precise and efficient material removal to achieve the desired product specifications.

Milling is a machining method where the material is cut by moving the workpiece beneath a rotating cutter with multiple teeth, resulting in a machined surface that can be flat, angular, or curved.

The cutting action of teeth on milling cutters can be quickly machined.  

Parts of Milling Machine

The main parts of the milling machine are following:

•  Base
•  Column
•  Knee
•  Saddle
•  Work Table
•  Spindle
•  Overarm
•  Arbor
•  Brace
•  Milling Cutter

 

Base

It consists of gray cast iron with precision-machined top and bottom surfaces, serving as the foundational component for all other parts of the machine.

Column

The column, a vertically cast member, is integrated with the base. These components of the milling machine house a comprehensive driving mechanism for the spindle and table feeds. The front vertical face undergoes precision machining, and the top of the column is finished to accommodate the overarm.

Knee

Constructed from robust gray cast iron, it smoothly moves vertically along the column’s wedge. The knee incorporates a table feed mechanism along with diverse controls. Its primary purpose is to provide support for saddles, work tables, and clamping devices for the workpiece.

Saddle

Atop the knee sits a saddle, sliding along the face of the column on guideways set precisely at 90° angles. The upper surface of the saddle undergoes precision machining to establish guideways for the table.

Work Table

The work table stands out as a crucial component of a milling machine, providing a secure hold for the workpiece during various operations. Its top surface undergoes precise finishing, featuring ‘T’ slots designed for securely clamping the workpiece and other fixtures.

Spindle

Situated at the upper part of the column, the spindle revolves, drawing power from belts, gears, and clutches before transmitting it to the arbor.

Overarm

Positioned at the column’s summit, it ascends in front of the column face and is frequently employed to provide support for both the arbor and spindle.

Arbor

These are extensions of spindles, where milling cutters are held and rotated.

Brace

A brace serves as an extra support, installed between the knee and the overarm to enhance the strength of both the arm and knee.

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Milling Cutter

It holds utmost significance in a milling machine as it facilitates various milling operations through the use of milling cutters.

It is a multipoint cutting tool in a milling machine.

Types of Milling Machine

There are following types of milling machines are used:

•  Column and Knee Type
•  Fixed Bed Type 
•  Planner Type 
•  Special Type 

Column and Knee Type 

Above shown in the figure the milling machines are the column and knee types.

Column and knee type milling machines can be classified into three categories.

• Plane/Horizontal Milling Machine
• Vertical Milling Machine
• Universal Milling Machine.  

Plain/Horizontal Milling Machine

It possesses greater strength compared to numerous other milling machine types. These machines allow the table to be fed in three directions: longitudinally, vertically, and crosswise.

Vertical Milling Machine

The vertical milling machine distinguishes itself from the horizontal milling machine based on the spindle’s orientation, as its spindle rotates along the vertical axis.

Universal Milling Machine

The universal milling machine bears a resemblance to a plain milling machine in its structure. However, beyond its capability for movement in three directions, the table can also be swiveled along the horizontal axis. This type of milling machine accommodates a broad range of milling tasks, including cutting helical gears and various straight and tapered works.

Fixed Bed Type Milling Machine

Characterized by its substantial weight, this machine has a table directly connected to the fixed bed wedge. The table can move reciprocally at right angles along the spindle axis. Unlike other types, there is no mechanism for cross or vertical adjustment. In these machines, the milling cutter is affixed to the spindle head, which can move vertically along the column, and the spindle can also be adjusted horizontally for cross adjustments.

Planer Type Milling Machine (Plano – Miller)  

It is large in shape and is used for heavy duty work.  

Spindle heads can be adjusted vertically and in transverse directions.

Special Type Milling Machine

There are following special types of milling machines are used:

• Surface Milling Machine 
• Thread Milling Machine
• Gear Milling Machine 
• Copy Milling Machine 

Surface Milling Machine

This milling machine is employed for multi-production tasks. The spindle head is vertically adjustable and equipped with a milling cutter. In this machine type, the table is responsible for providing the feed movement.

Thread Milling Machine

A thread milling machine is utilized for the milling of threads.

Gear Milling Machine

A gear milling machine finds application in milling various types of gears. The cutting of gear teeth frequently involves milling, assisted by a dividing head. While small gears can be milled on a horizontal milling machine, larger gears demand specialized gear machines for milling.

Operation of Milling Machine

The commonly used milling operations are described below. 

• Plain Milling
• Face Milling
• Side Milling
• Straddle Milling
• Angular Milling
• Gang milling
• Form Milling 
• Profile Milling
• End Milling
• Saw Milling
• Milling of Keyways, Grooves, Slots
• Gear Cutting 
• Helical Milling
• Cam Milling
• Thread Milling

 

Plain Milling

Plain milling is a milling machine operation where a flat, horizontal surface is machined parallel to the axis of rotation of the plane milling cutter.

This is also called slab milling.

Face Milling

A face milling cutter, rotating vertically along the axis of the work surface, is employed for conducting these specific types of milling operations.

Side Milling

Side milling in a milling machine involves creating a flat surface on the side of the workpiece, achieved through the use of a side milling cutter.

Straddle Milling

Straddle milling, as performed on a milling machine, entails creating flat vertical surfaces on both sides of the workpiece. This is achieved by utilizing two side milling cutters mounted on the same arbor.

Angular Milling

Angular milling, conducted on a milling machine, involves shaping an angular surface on the workpiece at an angle different from the right angle along the axis of the milling machine spindle.

Unconventional Machining Process: Types, Working, Uses

Now, refer to the figure illustrating gang milling, form milling, end milling, and saw milling operations, which are detailed below.

Gang milling

Gang milling is a milling operation where multiple surfaces on the workpiece are machined by using either cutters of the same diameter or different diameters simultaneously mounted on the machine arbor.

Form Milling

Form milling is a milling operation that involves creating irregular contours using form cutters. These irregular contours can take shapes such as convex, concave, or any other desired form.

Profile Milling

This operation involves producing a complex-shaped outline on a workpiece based on a template or master die.

End Milling

End milling is a milling operation that creates a flat surface, which can be either vertical, horizontal, or at any desired angle.

Saw Milling

Saw milling is a milling operation where narrow slots or grooves are produced on the workpiece utilizing a saw milling cutter.

Milling of Keyways, Grooves, Slots

On a milling machine, keyways, grooves, and slots can be fashioned using various tools such as a plane milling cutter, slitting saw, end mill, or side milling cutter.

Gear Cutting

Gear cutting on a milling machine is achievable through the utilization of a form relieve cutter. This cutter can take the form of either a cylindrical or end mill type.

Helical Milling

Helical milling, performed on a milling machine, involves creating helical flutes or grooves on the outer surface of cylindrical or conical workpieces.

Cam Milling

Cam milling is a milling operation that entails crafting cams on a milling machine with the aid of a universal dividing head and vertical milling attachment.

Thread Milling

Thread milling is a milling machine operation where threads are generated using a single or multiple thread milling cutter. This specific operation is carried out on a specialized thread milling machine, capable of producing precision threads in both small and large quantities.

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So, my friends, in this discussion, I covered the components of a milling machine, various types of milling machines, and the operations involved in milling machines.

I trust that you have gained a comprehensive understanding of all aspects discussed in this topic.

Thank you.